Corsair DDR PC-3500 vs. DDR PC-3200??

I have recently purchased an ASUS P4P800 Deluxe motherboard. I had pulled a P4 2.53 processor from my old machine and placed it into the new board. The new motherboard specs call for XMS Extreme Memory Speed Series 184 Pin 512MB DDR PC-3500 if I was to use the Corsair brand, in which I bought. Being the n00b that I am in computers as well as memory modules, and initially thinking the modules were backward compatible, I picked up 2 sticks of Corsair XMS Extreme Memory Speed Series 184 Pin 512MB DDR PC-3200 instead of the 3500. To my amazement, not only do I have excessive boot time (normally 1-1.5 minutes), but the majority of programs I use either lock up after a certain period of time, or are very slow to close. Running multiple programs is a definite no no on this machine and gaming loadtime appears to be extremely tasking for my system. Now, bear in mind that these are the same programs I had once used on a ASUS P4PE with the same processor and only a 512 stick of Kingston PC2700 that ran fine. I have made certain every start-up program was disabled thinking that may resolve the problem in "msconfig", but to no avail. Everything in BIOS concerning RAID has been disabled, other then that, the settings are stock. Figuring the BIOS needed updating, it has been flashed to the latest 1016 version. Running tests on the processor and the board turned out fine on Sandra, I have no Viruses or Spyware, and the system gets cleaned, defragged weekly. After researching the problem for a couple months now (since February), I am on the verge of canning something. Can anyone give some advice on this. And also can anyone tell me the differences in the two memory modules? Maybe the 3200 just will not work. Any and all help is definitely appreciated.

Unless you're overclocking, the PC3200 should work just fine up to an 800FSB. However, unless you picked up a TwinX pack, they're not gauranteed to run together with the same latencies as they are individually rated and they are not gauranteed to run in dual-channel. You might want to run [url=www.memtest86+]Memtest86+[/url] and see if it throws you any errors. If so, try one module at a time. What is the full part number of your modules, btw? You might have the latencies setup incorrectly which might cause this. The only other thing I can suggest is that a hard drive is going bad. It took me 5-10 minutes to boot the last time one of mine went out and it took forever to read or write anything once it did boot. PLUR CK